Lack of feedback on a returned phone, which stopped working within two weeks of being bought

I bought a Samsung cellphone from Ackermans in Vangate Mall on the 30th of June 2024. It worked for 12 weeks and the screen went black. I took it back to them for replacement on the 14th of June and to date, I have not gotten a replacement phone or my repaired phone back and no one is able to give any information. I have been to the 3 times already with no acceptable feedback.